P0496 Chevy Express: High Purge Emissions System Evaporative Emissions System

This is one of the most commonly encountered trouble codes for the Chevy Express Is the Code P0496. Refers to a code that you receive when your Express is plugged into an OBDII scanner.

Similar: P0420 Chevy Express

Chevy Express P0496 Symptoms

A P0496 code on the Chevy Express is often accompanied with an erratic idle. To find the correct idle speed, the engine will increase and decrease in revs. This can often occur right after buying gas. Sometimes it might not even start at the station.

If you’re old enough to have driven a carbureted vehicle the old stomp the gas and crank the engine method does actually help start the car. The air fuel mixture is off.

Chevy Express P0496 Significance

P0496 stands for a universal OBDII Trouble Code. The code can be used regardless of the make and model of your vehicle. The code is technically:

Evaporative Emissions System High Purge Flow

The EVAP captures any fuel vapor in the fuel tank. They are then sent to the intake to incite the regular combustion process.

If the Chevy Express computer notices that the EVAP is not purging properly, the code P0496 will be thrown.

Chevy Express P0496 Diagnoses

Many things can lead to the Chevrolet Express P0496 code. These are some of the more common issues that can cause the P0496 code to appear.

Vapor Canister Purge Valve– The most common culprit with the P0496 trouble code and the Chevy Express is going to be the vapor canister purge valve. When it goes bad, it typically causes issues with the vehicle’s idle speed. It is particularly true after filling up your vehicle.

It’s really easy to replace. You will need to locate and delete a few clips. The following YouTube video demonstrates how to fix the problem.

PCM– It is possible that the engines computer system itself has gone bad and is registering a P0496 when it shouldn’t be. However, you shouldn't start there.

Connectivity– It is possible for shorts in the wiring harness leading to the Vapor Canister Purge Valve has gone bad. It is worth checking.

Fuel Cap– A bad fuel cap can cause the P0496 code to be thrown for sure. Often, you’ll get a message informing you that the fuel cap is off even when it is on. It may be worth your time to change the fuel cap on your Chevy Express and wait to see if it disappears.

Oil Tank Pressure Sensor– If the fuel tank pressure sensor has gone bad, it can cause all sorts of problems, including the P0496 code.

Here’s a good video on it:

We wish you all the best in finding out what's wrong with your Express. We trust this helped. Please feel free to add anything below.